The headline feature of the P1000 is its zoom lens, which covers a range of 24-3000mm (equiv). That's wide enough to capture landscapes or interiors at the wide end, and closeup shots of the moon at the telephoto settings. .
The successor to the P900 feature lens that opens up to f/8 at the long end versus f/6.5 on the P900, but that tradeoff may be worth it for the extra reach - at that focal length, you'll want to use a tripod anyway. Both cameras' lenses start at f/2.8 and are paired with an understandably small 16-megapixel 1/2.3-inch BSI-CMOS sensor.
The P1000 is obviously designed for extreme zoom scenarios. The camera can also shoot 4K video at 30 frames per second, has a 2.3 million-dot OLED electronic viewfinder in addition to a rear-mounted, 3.2" 921k-dot LCD. The camera supports RAW image capture, and works with Nikon's SnapBridge Bluetooth image transfer system. It weighs 3.1 pounds / 1.4 kilograms. A stereo microphone is built in, and there's a socket for an accessory mic if you need better sound. The EVF is a significant upgrade compared to the 921k-dot viewfinder of the older P900, but the P1000's rear screen is unchanged compared to its predecessor.
Nikon is pricing the P1000 at $999 with availability to be scheduled for September.